Most historians agree that warfare in the Middle Ages cannot be studied in isolation. By its very definition, war—organized violence by groups against other groups—reflects the societies involved and, in turn, shapes them. This dynamic was especially true in the high medieval period, when military needs fueled administrative developments in finance, organization, recruitment, supply, and the tools of government itself. Before then, however, the very deterioration of such structures would limit the forms that warfare could take. Larger cultural issues would likewise play off of, and be played upon, by war. The Christian Church spent centuries trying to restrain or redirect the violence of its newest converts, the Germanic peoples. In time, however, the Church would find itself inextricably entangled in violent endeavors. On the secular side, the cult of chivalry developed first as the expression of a new, knightly identity; once in place, this new ethos sometimes had its own power to shape the contours of battle.